What happens to highly complex systems that try to manage or pre-determine every risk and outcome?
They collapse.
This nation didn’t try to determine every risk and outcome, it had the chance by restricting travel to extensively diminish any need for ebola scares. They could make it so mind numbingly hard for ebola infectees to make it all the way to the U.S. with travel restrictions. Now we have to deal with who knows how many false alarms, it makes the government look really awful. It also doesn’t look good for whomever elected a politician or politician who dropped the ball. Because incompetent voters make for incompetent politician.